Do not emit fat LTO objects when not needed

Author: antoyo

src/back/write.rs

@@ -64,8 +64,6 @@ pub(crate) fn codegen(
                     );
                     context.add_command_line_option("-flto=auto");
                     context.add_command_line_option("-flto-partition=one");
-                    // TODO(antoyo): remove since we don't want fat objects when it is for Bitcode only.
-                    context.add_command_line_option("-ffat-lto-objects");
                     context.compile_to_file(
                         OutputKind::ObjectFile,
                         bc_out.to_str().expect("path to str"),